Temperatures closer to the coast will be a few degrees warmer, and areas farther inland will be a few degrees cooler.

However there’s a pretty broad discrepancy in the forecast models in how cold it’s really going to get. The GFS model forecasts, for example, is the coldest with respective low temperatures of 25 and 18 degrees for the two mornings. The European model predicts 29 and 26 degrees. The mesoscale NAM model, which has higher resolution, forecasts 26 and 23 degrees.

The European forecast model is not as aggressive with the cold as other models. (Weather Bell)

So what we can say is that it’s going to be brutally cold on both mornings, and on Tuesday morning there’s the potential for record cold. The coldest temperature recorded on that date is 19 degrees, back in 1970.

The significance of the colder forecast is that if temperatures do fall to near 20 degrees, or below, for the central and northern parts of the Houston area precautions to protect pipes are warranted.

The threshold temperature for most pipes — those in attics and other areas not directly exposed to the cold — is about 20 degrees. What can you do about it? The following resource from the Institute for Business and Home Safety is about as good as it gets.

As it turns out, pipes don’t break where the ice develops and expands the pipe, but rather it’s due to downstream pressure between a blockage and a closed faucet.

Among their suggestions to prevent this from occurring:

• Seal all openings where cold air can get at unprotected water pipes. It’s especially important to keep away cold wind, which speeds freezing.

• Leave cabinet doors open under the kitchen and bathroom sinks to allow warmer room air to circulate around pipes.

• Let faucets drip slowly to keep water flowing through pipes that are vulnerable to freezing. Ice might still form in the pipes, but an open faucet allows water to escape before the pressure builds to where a pipe can burst. If the dripping stops, it may mean that ice is blocking the pipe; keep the faucet open, since the pipe still needs pressure relief. Also, don’t forget to turn the pipes off after the hard freeze — we just got out of a drought!

The freezing weather should end on Tuesday, as a warm, onshore flow from the Gulf of Mexico returns. I expect we’ll be back in the 70s, or near them, during the second half of the week.

Finally, we’d welcome your cold weather photos here at the Chronicle. You can send them to photos@chron.com. And do let me know how you’re preparing for the cold blast that’s hitting today, and then in full force tonight.

As it turns out, pipes don’t break where the ice develops and expands the pipe, but rather it’s due to downstream pressure between a blockage and a closed faucet.
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Interesting tidbit. I’m not going to do much aside from wrapping the little bit of exterior pipe I have and will leave those dripping.

Several large warm dogs lying on one’s feet.
Warm casseroles or soups on the menu
Several good movies to watch
Keeping the house toasty warm so the pipes don’t freeze.
Ordering seeds and making plans for the garden for spring.